Published April 19, 2024 | Published
Journal Article Open

Cyclic-loading effects in sand: a micromechanical study considering particle breakage

  • 1. ROR icon California Institute of Technology

Abstract

This paper investigates the response of Ottawa sand to cyclic loading using virtual oedometer tests and the level-set discrete element method. We study both the macroscopic and the micromechanical behavior, shedding light on the grain-scale processes behind the cyclic response observed in crushable sand, namely stress relaxation under strain control and ratcheting under stress control. Tests without particle breakage first show that asymmetrical frictional sliding during loading-unloading induces these cyclic-loading effects. Then, tests considering particle breakage reveal more pronounced stress relaxation and ratcheting, which decrease in rate over cycles, accompanied by increased frictional sliding and reduced particle contact forces. It is found that the broken fragments unload the most and promote an enhanced cushioning effect. These micromechanical processes contribute to a decrease in breakage potential as the cycles progress, implying that cyclically loaded materials may become more resistant to breakage when compared to the same material loaded monotonically at the same strain level. These new insights highlight the main contributions of the present work, factoring in real particle shapes from 3D X-ray tomography and notably contributing to the existing literature on the topic, where most studies rely on idealized particle shapes and rarely consider crushable grains.

Copyright and License

Copyright © 2024, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature

Funding

This work was supported by NSF (Award Number 2033779).

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Additional details

Created:
October 14, 2024
Modified:
October 14, 2024